Air field ground light



Sept' 11, 1956 .1. B. DE BOER AIR FIELD GROUND LIGHT Filed Sept. 4, 1952United States Patent O "ice ATR FIELD GROUND LIGHT Johannes Bernardus deBoer, Eindhoven, Netherlands,

assignor to Hartford National Bank and Trust Company, Hartford, Conn.,as trustee Application September 4, 1952, Serial No. 307,767

Claims priority, application Netherlands October 4, 1951 `1 Claim. (Cl.24U-1.2)

This invention relates to ground lights and more particularly to groundlights for air iields.

The term ground light is to be understood to mean a light iitting foruse on air ields for indicating runways, obstacles and the like,comprising a base which is sunk into the ground in such manner that itsupper surface is located at the level of the eld. Other lights which areerected almost completely above the ground level of airiields are notincluded in the term ground lights.

As a rule, a ground light is constituted by a base, an electric lampholder, a light source and an optical system beaming rays of the lightsource in the desired manner. It is evident that, as an alternative,more than one lamp holder, light source and optical system may becombined in one ground light.

The object of the invention is to provide a construction for a groundlight having a very compact structure.

The ground lights hitherto used were constructed so that at least thelamp holder and the lamp were arranged inside the base below groundlevel. The invention, however, is based on the recognition of the factthat a lamp is comparatively inexpensive, so that its destruction is ingeneral less disadvantageous than the destruction of the known assembly,while the construction of the base may be much lighter in weight andless voluminous if the lamp is not arranged inside the base.

According to the invention a ground light is characterized in that thebase containssolely a lamp holder with current supply members, whereasthe envelope of the light source or sources and the optical system orsystems are positioned above the base.

The light source may be provided with a separate optical system, or anenvelope of the light source itself may constitute the optical system.For example, an incandescent lamp may be used in which part of the bulbis a reecting surface.

In order to obtain an inexpensive construction for a lamp holder andavoid the risk of water penetrating into the iitting, in one embodimenta watertight sealing means, for example, a rubber ring, is providedbetween the lamp cap of a light source and the base. Said rubber ringprevents water from penetrating to the contacts of the lamp holder andis preferably located under the upper surface of the base, so that it isnot damaged in case of a collision which would destroy the lamp and theoptical system. Despite the destruction of the lamp and the opticalsystem, the

2,762,905 Patented Sept. 11, 1956 interior of the base remains protectedagainst the penetration of moisture.

In order that the invention may be readily carried into effect, it willnow be described in greater detail with reference to one embodimentshown, by way of example, in the accompanying drawing in which;

The figure is a sectional view of a ground light according to theinvention.

The ground light is constituted by a receptacle 1, which may be made ofcast iron. Said receptacle may be dug directly into the ground, but inmost cases it should iirst be secured in a block of cement or concretewhich is sunk in the ground.

The receptacle comprises a cavity 2, which is closed by a disc 3. Thelatter is urged by a plurality of screws 4 on a rubber sealing ring 5.The receptacle together with the disc and sealing ring constitute thebase of the fitting. The disc 3 comprises an aperture into which a lampholder 6 is inserted from the bottom and fixed in position with the useof screws 7. A current supply cable 8 connected to the lamp holder isled in through an aperture of the base which is sealed by a tighteningnut 9 and a rubber ring 10. An incandescent lamp 11 is placed in theholder 6, a rubber ring 13 for sealing being provided between the lampcap 12 and disc 3 and lamp holder 6.

A silver-plated part 14 of the bulb of the incandescent lamp is in thiscase shaped in such manner as to provide the desired beaming of thelight. In addition the bulb is provided with a hood 15 which ismanufactured from, for example, thin sheet metal and which preventsunwanted stray of the light.

The figure shows that in case of a collision the cap 15 and the lamp 11will be destroyed, but that there is no risk of moisture penetrating tothe interior of the base 1, since the lamp cap 12 will not allow thepassage of water and the penetration of moisture along the lamp cap isprevented by the rubber ring 13.

It is evident that many variations in the form and construction of theparts above the ground are possible.

What I claim is:

A ground light of the type used on an airfield consisting of areceptacle, an apertured closure member in said receptacle, meansremovably securing said closure member in said receptacle, a lamp holderin said aperture, a lamp bulb in said holder, a reflector on said bulb,all elements of said ground light being positioned below ground levelwith the exception of said lamp bulb and reilector whereby when saidground light is struck by a portion of an airplane only the lamp bulband reflector are damaged.

References Cited in the file of this patent UNITED STATES PATENTS428,564 Jenks May 20, 1890" 480,201 Meadows Aug. 2, 1892 2,006,839Moller July 2, 1935 2,191,379 Glasgow Feb. 20, 1940 2,246,808 McKechnil.lune 24, 1941 2,332,362 Bartow Oct. 19, 1943 2,378,823 Bartow June 19,1945-

